Steric and electronic effects on the 1H hyperpolarisation of substituted pyridazines by signal amplification by reversible exchange. (5th April 2021)

• Record Type: Journal Article
• Authors: Rayner, Peter J.; Burns, Michael J.; Fear, Elizabeth J.; Duckett, Simon B.
• Other Names: Mewis Ryan E. guestEditor.
• Is Part Of: Magnetic resonance in chemistry. Volume 59:Number 12(2021)
• Page Start: 1187
• Page End: 1198
• Publication Date: 2021-04-05
• Subjects: hyperpolarisation -- NMR -- parahydrogen -- SABRE; Nuclear magnetic resonance spectroscopy -- Periodicals; Chemistry, Organic -- Periodicals; Magnetic resonance -- Periodicals; 538.36
• DOI: 10.1002/mrc.5152
• Languages: English
• ISSNs: 0749-1581

Abstract

Abstract: Utility of the pyridazine motif is growing in popularity as pharmaceutical and agrochemical agents. The detection and structural characterisation of such materials is therefore imperative for the successful development of new products. Signal amplification by reversible exchange (SABRE) offers a route to dramatically improve the sensitivity of magnetic resonance methods, and we apply it here to the rapid and cost‐effective hyperpolarisation of substituted pyridazines. The 33 substrates investigated cover a range of steric and electronic properties and their capacity to perform highly effective SABRE is assessed. We find the method to be tolerant to a broad range of electron donating and withdrawing groups; however, good sensitivity is evident when steric bulk is added to the 3‐ and 6‐positions of the pyridazine ring. We optimise the method by reference to a disubstituted ester that yields signal gains of >9000‐fold at 9.4 T (>28% spin polarisation). Abstract : SABRE enables pyridazines to be detected by 1 H NMR with greater than 28% polarisation.